PSMC3 promotes RNAi by maintaining AGO2 stability through USP14.

BACKGROUND: Argonaute 2 (AGO2), the only protein with catalytic activity in the human Argonaute family, is considered as a key component of RNA interference (RNAi) pathway. Here we performed a yeast two-hybrid screen using the human Argonaute 2 PIWI domain as bait to screen for new AGO2-interacting proteins and explored the specific mechanism through a series of molecular biology and biochemistry experiments. METHODS: The yeast two-hybrid system was used to screen for AGO2-interacting proteins. Co-immunoprecipitation and immunofluorescence assays were used to further determine interactions and co-localization. Truncated plasmids were constructed to clarify the interaction domain. EGFP fluorescence assay was performed to determine the effect of PSMC3 on RNAi. Regulation of AGO2 protein expression and ubiquitination by PSMC3 and USP14 was examined by western blotting. RT-qPCR assays were applied to assess the level of AGO2 mRNA. Rescue assays were also performed. RESULTS: We identified PSMC3 (proteasome 26S subunit, ATPase, 3) as a novel AGO2 binding partner. Biochemical and bioinformatic analysis demonstrates that this interaction is performed in an RNA-independent manner and the N-terminal coiled-coil motif of PSMC3 is required. Depletion of PSMC3 impairs the activity of the targeted cleavage mediated by small RNAs. Further studies showed that depletion of PSMC3 decreased AGO2 protein amount, whereas PSMC3 overexpression increased the expression of AGO2 at a post-translational level. Cycloheximide treatment indicated that PSMC3 depletion resulted in a decrease in cytoplasmic AGO2 amount due to an increase in AGO2 protein turnover. The absence of PSMC3 promoted ubiquitination of AGO2, resulting in its degradation by the 26S proteasome. Mechanistically, PSMC3 assists in the interaction of AGO2 with the deubiquitylase USP14(ubiquitin specific peptidase 14) and facilitates USP14-mediated deubiquitination of AGO2. As a result, AGO2 is stabilized, which then promotes RNAi. CONCLUSION: Our findings demonstrate that PSMC3 plays an essential role in regulating the stability of AGO2 and thus in maintaining effective RNAi.

RNA N6-methyladenosine modification mediates downregulation of NR4A1 to facilitate malignancy of cervical cancer.

BACKGROUND: N6-methyladenosine is the most abundant eukaryotic mRNA modification and alters a wide range of cellular processes in cancer. Therefore, defining the molecular details are critical for understanding the regulatory mechanism of m6A modification. RESULTS: We found that METTL3, a core m6A methyltransferase component, is upregulated and functions as an oncogene in cervical cancer. Mechanistically, METTL3 induces the degradation of m6A-modified transcripts of NR4A1 though YTHDF2-DDX6 pathway. In addition, NR4A1 overexpression attenuates the malignant progression through recruiting the LSD1/HDAC1/CoREST transcriptional repression complex to AKT1 promoter. CONCLUSIONS: Our findings reveal that m6A regulates cervical cancer cellular progression through manipulating NR4A1 pathway.

Human cancer cells generate spontaneous calcium transients and intercellular waves that modulate tumor growth.

Electrically excitable cells such as neurons transmit long-distance calcium or electrical signals to regulate their physiological functions. While the molecular underpinnings and down-stream effects of these intercellular communications in excitable cells have been well appreciated, little is known about whether and how non-excitable cancer cells spontaneously initiate and transmit long-distance intercellular signals. Here we report that non-excitable human colon and prostate cancer cells spontaneously initiate and spread intercellular calcium waves, in vitro and ex vivo. Xenograft model studies suggest that these calcium signals promote the growth rate of tumors in mice. Pharmacological studies elucidated that the inositol-trisphosphate-receptor (IP3R)-regulated calcium release from endoplasmic reticulum (ER), which is activated by the Gq-PLC-IP3R pathway, is a major cause for the initiation of spontaneous calcium transients. Further, the spatial-temporal characteristics of calcium dynamics can be tuned by the culture substrates of different mechanical stiffnesses. Our results provide evidence that calcium dynamics enables long-distance functional communication in non-excitable cancer cells and offer the potential to modulate calcium signaling for new cancer therapies.

Differences between novel hybrid mode flaps and traditional perforator flaps at the level of metabolites using LC-MS.

The multi-territory perforator flaps are widely used in plastic surgery. However, partial necrosis flap in the potential territory remains a challenge to plastic surgeons. We raised a novel "hybrid nourished mode" (HNM) flap based on the multi-territory deep inferior epigastric perforator (DIEP) flap to improve flap survival. Thirty-two rabbits were randomly divided into DIEP and HNM groups. Untargeted metabolic mechanisms between the DIEP and HNM groups were performed using LC-MS under the filter criteria of fold change >20.0 times or <0.05, and variable importance in projection (VIP) value was set at ≥1, P < 0.05. Between the two groups, flap survival, perfusion, microvasculature, histopathology, and immunohistochemistry of CD31 were assessed on post-operative day 7. We screened 16 different metabolites that mainly participated in biosynthesis of secondary metabolites, aminoacyl transfer RNA biosynthesis, phenylalanine metabolism, arginine and proline metabolism, among others. The results of the HNM flaps were higher than those of the DIEP flaps (P < 0.05) in the aspects of flap survival, flap perfusion, and microvasculature. Compared with the DIEP flaps, HNM has a stronger advantage in tissue metabolism. This study provided us with a better understanding and strong evidence in terms of metabolites on how HNM achieves the survival of large multi-territory perforator flaps.

Isolation and genomic analysis of temperate phage 5W targeting multidrug-resistant Acinetobacter baumannii.

Temperate phages are potential therapeutic agents, but only a few temperate phages infecting multidrug-resistant Acinetobacter baumannii have been identified. In this study, we isolated 5W, a temperate phage that infects multidrug-resistant A. baumannii, from pond water using the enrichment method. A member of the Siphoviridae family, 5W has a narrow host range and infected only four of 19 A. baumannii clinical isolates. It exhibited rapid adsorption (> 90% in 6 min), a latency period of 20 min, and a burst size of ~ 180 plaque-forming units (PFU/cell). 5W contains a linear double-stranded DNA (dsDNA) genome of 43,032 bp with a GC content of 39.85%. The 5W genome contains 61 open reading frames, including lysogen-forming genes, but lacks any known virulence and antibiotic resistance genes. The lysin of 5W is an N-acetyl-ß-D-muramidase belonging to the GH_108 family. The α-helical structure and highly positively charged amino acids in the C-terminal region indicate potential antibacterial activity against A. baumannii, and the M/S subunits of the restriction endonuclease are inserted into the lysogenic gene cluster. Comparative genome analysis revealed high similarity with two different prophages in A. baumannii ABCR01, suggesting that 5W may be derived from recombination of other prophages.

The effect of different modes of microneedling technique on random flap survival in rats.

OBJECTIVE: The investigation and practice of physical therapy in flap surgery are still scare. The purpose of this study is to evaluate the impact of different microneedling interventions on survival of random pattern flaps in rats, attempting to determine the optimal microneedling protocols for improvement of flap survival. METHODS: Eighty male Sprague-Dawley rats were randomly divided into four groups, with 20 in each group (group A, B, C, and D). A 3 cm × 9 cm rectangular random flap as the McFarlane flap was adopted in each group. In groups A and B, microneedling treatment was performed before and after surgery, respectively. While animals in group C were received both pre- and postoperative microneedling treatment. Group D was used as a control group, which was only exposed to surgery. Flap survival, flap blood flow, number of capillary formations, the expressions of CD31, CD34, HIF-1α, and vascular endothelial growth factor (VEGF) were detected in each group and compared. RESULTS: On the 7th day postoperatively, significant improvements with microneedling treatment were found in flap survival rate (p = 0.007), blood flow (p = 0.024), the expression levels of CD34 (p = 0.005), and the VEGF (p < 0.01). Furthermore, the VEGF expression level was significantly higher in group B when compared with the other three groups (all p < 0.01). However, there was no significant difference in the number of new blood vessels and other immunohistochemical indicators among the four groups (all p > 0.05). CONCLUSION: Microneedling treatment especially postoperative intervention can significantly improve the survival of random flaps in rats.

A metabolic investigation of arterialized venous flaps in rabbits using mass spectrometry-based metabolomics.

An arterialized venous flap (AVF) is an ideal choice of flap to repair wounds. However, the survival of these flaps remains the source of some concern. This study used metabolomic analysis to investigate the mechanisms underlying survival in AVF flaps in order to guide the clinical application of these flaps. Thirty-six male Japanese rabbits were randomly divided into a sham group and an AVF group. They were used for histology and hemodynamic investigations. Three days after surgery, tissue samples were analyzed by mass spectroscopy-based metabolomics. The results of the study revealed a reduction in blood flow, infiltration of inflammatory cells, and necrosis of flaps in the AVF group. In addition, notable changes were evident in the levels of several metabolites in the AVF group, including lactic acid, acetoacetic acid, inositol phosphate, arachidonic acid, and other metabolites. Our results indicate that the AVF group experienced changes in several biological pathways, including energy metabolism, cell membrane stability, and inflammatory response. There is a significant metabolic difference between AVFs and physiological flaps. The dysregulation in certain metabolites may be related to the specific hemodynamics and insufficient energy metabolism of the AVFs.

The efficacies and limitations of fasciectomy and collagenase clostridium histolyticum in Dupuytren's contracture management: A meta-analysis.

BACKGROUND: We intend to assess the efficacies and limitations of collagenase clostridium histolyticum (CCH) and fasciectomy in treating Dupuytren's contracture, and the associated complications and rate of recurrences aiming to present a treatment algorithm. METHODS: A literature search within the PubMed, Web of Sciences, Cochrane Library, and EMBASE databases was performed using the combined key words 'Dupuytren, palmar aponeurosis contracture, collagenase clostridium histolyticum and fasciectomy', including all possible studies with a set of predefined inclusion and exclusion criteria. RESULTS: Thirty studies were assessed for eligibility from 215 identified records. Seventeen publications satisfied the inclusion criteria including 2142 joints in 1784 patients. The mean follow-up time was 18.0 months (3-60). CONCLUSION: Acceptable contractures release was obtained in both techniques. Severe complications associated with fasciectomy outrank those of CCH, whereas the low rate of recurrence favors the fasciectomy technique.

The feasibility and survival mechanism of a large free flap supported by a novel hybrid perfusion mode.

OBJECTIVES: In this study, we presented a novel hybrid perfusion mode in an attempt to provide a new strategy to improve the survival of an extended large flap and discuss its possible mechanisms. MATERIALS AND METHODS: A 14 × 10 cm flap was designed on the rabbit abdomen. Ninety-six rabbits were randomly divided into three groups based on the flap perfusion mode: control group I (CON 1, physiological perfusion mode with bilateral deep inferior epigastric vascular pedicles intact), control group II (CON 2, physiological perfusion mode with single deep inferior epigastric vascular pedicle intact), hybrid nourished group (physiological perfusion as in CON 2 combined with arterialized venous nonphysiological perfusion mode, referred to as a hybrid perfusion mode). Flap survival, status of vascular perfusion, microvasculature, histopathology, expression of CD34, eNOs, VEGF and metabolic status of the flaps by LC-MS were assessed in each group. RESULTS: The results of "hybrid nourished" flaps were similar to the traditional flaps in terms of flap survival, level of vascular perfusion and microvasculature except the status of metabolites. CONCLUSIONS: The feasibility of this novel hybrid perfusion mode will greatly extend the indications of flap transfer and efficiently improve the survival reliability of large flaps. In a sense, this mode will be an ideological emancipation for the field of flap surgery.

Fabrication of MCC/Cu2O/GO composite foam with high photocatalytic degradation ability toward methylene blue.

In this work, cuprous oxide (Cu2O) particles and graphene oxide (GO) nanosheets were simultaneously incorporated into the microcrystalline cellulose (MCC) foam to fabricate the MCC/Cu2O/GO composite foam toward methylene blue (MB) photocatalytic degradation. The interaction between Cu2O and GO and the morphologies of the composite foams were investigated. The results showed that there was a hydrogen bonding interaction between Cu2O and GO, which promoted the exfoliation of GO nanosheets and the dispersion of Cu2O in the composite foam. The MCC/Cu2O/GO composite foams not only exhibited high photocatalytic degradation ratio toward MB compared with the pure Cu2O particles and the common MCC/Cu2O composite foams, but also exhibited much higher derogation rate compared with the Cu2O-based photocatalytic degradation materials as reported in literature. A concept of 'micro-reactor' was proposed to explain the mechanisms for the largely enhanced degradation rate. Furthermore, the cycling measurements for the photocatalytic degradation of MB was also evaluated.

The management of degloving injuries of the limb with full thickness skin grafting using vacuum sealing drainage or traditional compression dressing: A comparative cohort study.

BACKGROUND: Degloving injuries of the limb are severe and frequently underrated. Few researches are available comparing the results of reattachment of the degloved skin grafts with the vacuum sealing drainage technique and the traditional compression dressing method. In this study, we aimed to compare the treatment outcomes of these two approaches. METHODS: Eighty-three consecutive patients were treated for degloving injury of the limb. Based on the treatment approach, the patients were divided into vacuum sealing drainage group (VSD group, n = 55) and traditional compression dressing group (TCD group, n = 28). After reattachment, the degloved skin was secured with stitches and compressed with VSD or TCD. The outcomes were mainly assessed based on the percentage of skin graft take. RESULT: In VSD group, there were excellent results in 18, fair in 9 and poor in 28, respectively; In TCD group, there were excellent results in 11, fair in 10 and poor in 7, respectively. Statistically, no significant difference was found between two groups in terms of the category of excellent results. However, significant higher incidence of poor results with necrotic areas exceeding 50% was observed in the VSD group than that in the TCD group. In addition, although the duration of hospitalization in the VSD group was shorter than that in the TCD group, the medical supply costs and total costs were much higher than that of the TCD group. CONCLUSION: VSD and TCD are equally effective in the management of degloving injuries of the limb; however, VSD technique may potentially have a higher risk of poor results with increased hospital charges. The traditional approach still has its merits in clinical practice, especially in rural hospitals when VSD is not available or unaffordable.

Allogenic endothelial progenitor cell transplantation increases flap survival through an upregulation of eNOs and VEGF on venous flap survival in rabbits.

BACKGROUND: Endothelial progenitor cells (EPCs) are one type of bone marrow hematopoietic stromal cells which play a vital role in neovascularization and tissue repair. In this study, we investigated whether EPCs promote flap survival in a rabbit venous model. MATERIALS AND METHODS: EPCs were customized from CHI Scientific, Inc, China. Thirty-six rabbits were randomly assigned to either the sham group (n = 12), the control group (n = 12) or the EPC transplantation group (n = 12). A 10 × 6 cm venous flap was created on the rabbit abdomen. Both the EPC transplantation and control groups had the same volume of EPCs-PBS (phosphate buffered saline) and PBS on postoperative day 1. Flap survival, blood flow, histopathology, expression of endothelial nitric oxide synthase (eNOs) and Vascular Endothelial Growth Factor (VEGF) were detected on postoperative day 10. RESULTS: Cellular immunofluorescence assay positively confirmed that the EPCs were undergoing differentiation. The survival rate of the flap in the EPC transplantation group was 58.4 ± 7.1%, which was significantly higher than that of the control group (4.8 ± 3.4%) (p<0.01). Histological examination revealed that the EPC transplantation group had higher microvessel density, fewer inflammatory cells, and a higher expression of eNOs and VEGF. Significantly increased blood flow perfusion was seen in the EPC transplantation group using laser Doppler imaging. The Western Blot technique revealed that the expression of eNOs and VEGF in the EPC transplantation group were both significantly higher than those in the control group. CONCLUSION: This study demonstrated that EPC transplantation improved venous flap survival in rabbits. The present findings may provide insight into the promotion of venous flap survival in clinical practice in the future.

Bilateral Locking of the Metacarpophalangeal Joint: A Case Report and Systematic Literature Review.

BACKGROUND: The purposes of this article were to present an exemplary case of bilateral locked metacarpophalangeal (MCP) joint of the second metacarpal and to review the literature for a more comprehensive understanding of this condition. METHODS: For the literature review, PubMed and Google Scholar research were performed using the term "metacarpophalangeal joint (MCP joint) locking or locked metacarpophalangeal joint (MCP Joint)" with a set of inclusion and exclusion criteria. RESULTS: We recently treated a patient with bilateral locked MCP, which presented to our office on 2 separate occasions in the space of 3 years. The left hand was affected in 2015 and the right hand in 2018. After clinical and imaging investigations, the patient was operated on. The patient had a locking of the accessory collateral ligament behind a radial sided prominence of the second metacarpal head. After surgery, the patient regained full function of her index finger. On the basis of our literature review, we found 47 cases described in the literature, plus our case, the index finger (22), and the long finger (11) were most commonly involved. CONCLUSION: Left untreated, the locked MCP joint may lead to a flexion contracture and disabilities in performing daily life activities. The diagnosis is mainly clinical. The radiographs can show degenerative changes or a particular shape of the metacarpal head/neck as a first clue to the possible cause. Gentle closed reduction can be attempted, but surgery is most often required. The surgical approach depends on the presumed localization of the pathology.